Article · Wikipedia archive · Last revised May 29, 2026

Trinitrogen

Trinitrogen, also known as the azide radical, is an unstable molecule composed of three nitrogen atoms. Two arrangements are known: a linear form with double bonds and charge transfer, and a cyclic form. Both forms are highly unstable, though the linear form is the more stable of the two. More-stable derivatives exist, such as when it acts as a ligand, and it may participate in azido nitration, which is a reaction between sodium azide and ammonium cerium nitrate.

Last revised
May 29, 2026
Read time
≈ 2 min
Length
441 w
Citations
9
Source
Wikipedia ↗
Trinitrogen
source ↗
source ↗
source ↗
source ↗
Names
Other names
Azide radical

Triazirene (cyclic)

Triazadienyl
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
770
  • InChI=1S/N3/c1-3-2
    Key: DUAJIKVIRGATIW-UHFFFAOYSA-N
  • cyclic: InChI=1S/N3/c1-2-3-1
    Key: RLXSTAGCZQYHDL-UHFFFAOYSA-N
  • linear: [N-]=[N+]=[N]
  • cyclic: N1=N[N]1
Properties
N3
Molar mass 42.021 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Trinitrogen, also known as the azide radical, is an unstable molecule composed of three nitrogen atoms. Two arrangements are known: a linear form with double bonds and charge transfer, and a cyclic form. Both forms are highly unstable, though the linear form is the more stable of the two.1 More-stable derivatives exist, such as when it acts as a ligand, and it may participate in azido nitration, which is a reaction between sodium azide and ammonium cerium nitrate.23

The linear form of N3 is similar to the azide anion and was discovered in 1956 by B. A. Thrush4 by photolysis of hydrogen azide.5 As a linear and symmetric molecule, it has D∞h symmetry, with a nitrogen–nitrogen bond length averaging 1.8115 Å. The first excited electronic state, A2Σu, is 4.56 eV above the ground state.1

The cyclic form was identified in 2003 by N. Hansen and A. M. Wodtke using ultraviolet photolysis of chlorine azide. Although the reaction yielded mostly the linear form, about 20% of the molecules were cyclic.41 The ring has C2v symmetry1—an isosceles triangle—in contrast to the linear form that has equal N–N bond-lengths.

References

References

  1. Hansen, N.; Wodtke, A. M. (December 2003). "Velocity Map Ion Imaging of Chlorine Azide Photolysis: Evidence for Photolytic Production of Cyclic-N3". The Journal of Physical Chemistry A. 107 (49): 10608–10614. Bibcode:2003JPCA..10710608H. doi:10.1021/jp0303319.
  2. Schlegel, H. Bernhard; Skancke, Anne (August 1993). "Thermochemistry, energy comparisons, and conformational analysis of hydrazine, triazane, and triaminoammonia". Journal of the American Chemical Society. 115 (16): 7465–7471. Bibcode:1993JAChS.115.7465S. doi:10.1021/ja00069a053.
  3. Kuchitsu, K, ed. (1998). Inorganic Molecules. Landolt-Börnstein - Group II Molecules and Radicals. Vol. 25A. doi:10.1007/b59072. ISBN 3-540-61713-2.
  4. Jin, Lin; Yu, Xue-fang; Pang, Jing-lin; Zhang, Shao-wen; Ding, Yi-hong (30 July 2009). "Theoretical Study on the Reactions of the Cyclic Trinitrogen Radical toward Oxygen and Water". The Journal of Physical Chemistry A. 113 (30): 8500–8505. Bibcode:2009JPCA..113.8500J. doi:10.1021/jp810741v. PMID 19719307.
  5. Thrush, B. A. (10 April 1956). "The Detection of Free Radicals in the High Intensity Photolysis of Hydrogen Azide". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 235 (1200): 143–147. Bibcode:1956RSPSA.235..143T. doi:10.1098/rspa.1956.0071. S2CID 95714517.
External links